The disclosed invention is directed generally to head-up displays for vehicles, and more particularly is directed to a head-up display which provides for reduced ghost image intensity.
Head-up displays are utilized in vehicles such as automobiles to produce virtual images of vehicle operating parameter indicators that appear to be ahead of the vehicle windshield and are therefore viewable by the vehicle operator without diversion of his or her eyes to an instrument panel inside the vehicle and without refocusing.
A known head-up display technique involves utilizing a vehicle windshield surface as a beam-splitter for partially reflecting imaging illumination incident thereon. However, as a result of the thickness of the vehicle windshield and reflections at a windshield surface that is not the primary or main reflecting surface, secondary or ghost images are produced. Depending on ambient lighting conditions, ghost image intensity can be sufficiently bright relative to the primary or main image intensity so as to be objectionable.